Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fixes from Thomas Gleixner:
 "The itimer removal one is not strictly a fix, but I really wanted to
  avoid a rebase of the urgent ones."

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "clocksource: Load the ACPI PM clocksource asynchronously"
  clockevents: tTack broadcast device mode change in tick_broadcast_switch_to_oneshot()
  itimer: Use printk_once instead of WARN_ONCE
  nohz: Fix stale jiffies update in tick_nohz_restart()
  tick: Document TICK_ONESHOT config option
  proc: stats: Use arch_idle_time for idle and iowait times if available
  itimer: Schedule silent NULL pointer fixup in setitimer() for removal

4 files changed, 15 insertions, 5 deletions

diff --git a/kernel/itimer.c b/kernel/itimer.c
index 22000c3db0d..8d262b46757 100644
--- a/kernel/itimer.c
+++ b/kernel/itimer.c
@@ -284,8 +284,12 @@ SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
         if (value) {
                 if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
                         return -EFAULT;
-        } else
-                memset((char *) &set_buffer, 0, sizeof(set_buffer));
+        } else {
+                memset(&set_buffer, 0, sizeof(set_buffer));
+                printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
+                            " Misfeature support will be removed\n",
+                            current->comm);
+        }
 
         error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
         if (error || !ovalue)
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 2cf9cc7aa10..a20dc8a3c94 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -1,6 +1,10 @@
 #
 # Timer subsystem related configuration options
 #
+
+# Core internal switch. Selected by NO_HZ / HIGH_RES_TIMERS. This is
+# only related to the tick functionality. Oneshot clockevent devices
+# are supported independ of this.
 config TICK_ONESHOT
         bool
 
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index e883f57a3cd..bf57abdc7bd 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -575,10 +575,12 @@ void tick_broadcast_switch_to_oneshot(void)
         unsigned long flags;
 
         raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
+
+        tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
+
         if (cpumask_empty(tick_get_broadcast_mask()))
                 goto end;
 
-        tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
         bc = tick_broadcast_device.evtdev;
         if (bc)
                 tick_broadcast_setup_oneshot(bc);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 3526038f283..6a3a5b9ff56 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -534,9 +534,9 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
                                 hrtimer_get_expires(&ts->sched_timer), 0))
                                 break;
                 }
-                /* Update jiffies and reread time */
-                tick_do_update_jiffies64(now);
+                /* Reread time and update jiffies */
                 now = ktime_get();
+                tick_do_update_jiffies64(now);
         }
 }